<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title>2.姓名案例_watch实现</title>
		<!-- 引入Vue -->
		<script type="text/javascript" src="../js/vue.js"></script>
	</head>
	<body>
		<!-- 准备好一个容器-->
		<div id="demo">
			姓：<input type="text" v-model="firstName"> <br>
			名：<input type="text" v-model="lastName"> <br>
			全名：<span>{{fullName}}</span>
		</div>

		<script type="text/javascript">
			//阻止 vue 在启动时生成生产提示。
			Vue.config.productionTip = false
			
			new Vue({
				el:'#demo',
				data:{
					firstName:'zhang',
					lastName:'san',
					fullName:''
				},
				watch:{
					firstName(value){
						this.fullName = value + this.lastName
					},
					lastName:{
						immediate:true,
						handler(value){
							this.fullName = this.firstName + value
						}
					}
				}
			})
		</script>
	</body>
</html>